The present invention relates to a process for producing shaped articles with patterns by using a molding compound (hereinafter referred to as MC). The present invention contemplates producing shaped articles with patterns by causing a plurality of unsaturated polyester resin compounds or compositions of different color tones to thicken, uniting the thickened compositions to produce a bulk molding compound (hereinafter referred to as BMC) or a sheet molding compound (hereinafter referred to as SMC), and producing a shaped article with patterns which consists of cured unsaturated polyester resins and has excellent clearness of patterns according to a desired design through the use of the resultant molding compounds. The term "molding" as used herein does not necessarily mean a molding process using a mold, but includes a molding process wherein an MC is merely placed on a molding plate, the roller molding process, and the calender molding process.
Attempts have been made heretofore to produce shaped articles with patterns, particularly shaped objects having marble-like patterns, without skillful fabrication and processing such as cutting, carving and polishing of marble. Among these, there have been proposed: (1) a casting method wherein coloring agents or colored fillers are incompletely dispersed in a matrix resin material comprising thermosetting resins such as unsaturated polyester resins, and the resultant dispersion is cast in a mold, debubbled, and cured; (2) and injection method wherein coloring agents are admixed into a debubbled base resin compound in an intermediate part of a supply line under pressure and the resulting blend is cured in a mold; and (3) an SMC method wherein a preformed sheet made of glass fibers is impregnated with a base or matrix resin, and coloring agents are added to the impregnated fiber sheet prior to roller pressing, thereby producing an SMC, the SMC being inserted between a male mold and a female mold to be formed under pressure into a shaped article.
All of these methods contemplate forming patterns by dispersing coloring agents in a base resin while forming light and shaded parts throughout the base resin. However, these methods are accompanied by the following problems.
(1) Because the pattern is mainly formed randomly by contingency or chance, there is little room for designing of a high quality pattern. The quality of the resultant pattern is non-uniform in most cases, and shaped articles having poor appearance have remarkably low commodity value. PA0 (2) Because the diffusion of the coloring agent due to interfusion between the pattern portions and the base portions, cannot be avoided, a clear and distinct pattern is difficult to produce, and the design performance is limited. This tendency is particularly conspicuous in the case of the injection method wherein a turbulent flow of colored resins tends to occur during injection. PA0 (3) Because the incompletely mixed coloring agent diffuses into the base resin with the lapse of time and, as a result, the pattern becomes obscure in the case of the casting method and the injection method, the mixed molding materials cannot be entirely stored in an uncured state before the shaping thereof. Accordingly, it is necessary to provide a process for mixing a coloring agent adjacent to a shaping process in each shaping station. Furthermore, because mixing of coloring agents entails the introduction of air into the base resin which adversely affects the quality of the final shaped product, it is necessory in some cases to provide a deaerating process adjacent to the process for mixing a coloring agent. PA0 (a) preparing a plurality of unsaturated polyester resin compositions of different color tones; PA0 (b) uniting the plural resin compositions after at least either one in each pair of the adjacent compositions to be united has been thickened; and PA0 (c) thickening all of the united resin compositions to form a solid or semi-solid molding compound.